• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.13-22
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• 1999

Both the resonance and ultrasonic techniques are standard methods far characterizing the physical properties of piezoelectric materials. However, we found that each technique can only offer a few reliable measurements while the rest often have errors or impossible to implement because of the sample requirements. This paper show that one can use the combination of both techniques to achieve much better accuracy and be able to get the complete set of elastic, dielectric and piezoelectric coefficients using fewer samples. Using an ultrasonic spectroscopy we have also measure the dispersion of the ultrasonic velocity and the attenuation up to 65 MHz. Pb(Zr,Ti)O$_3$[PZT] ceramics were used as examples fur both studies.

• 한국전산구조공학회논문집
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• 제16권2호
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• pp.183-195
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• 2003

본 연구에서는 판형태의 압전감지기와 압전작동기가 접착되어 있는 보형태의 스마트구조물의 자유진동제어에 대한 유한요소모형화 방법을 제안한다. 압전재료의 직접압전효과와 역압전효과에 대한 구성방정식을 고려하고 변분원리를 이용하여 스마트보유한요소의 운동방정식을 유도한다. 이러한 2절점 보 유한요소근 등매개변수요소로서 Timoshenko 보이론을 기초로 한다. 따라서, 보형태의 스마트구조물을 제안하는 스마트보 유한요소에 의하여 해석함으로써 전압이 작용되는 압전작동기에 의한 구조물의 제어와 전압을 측정하는 압전감지기에 의한 구조물의 모니터링에 대한 수치적인 시뮬레이션이 가능해진다 이러한 스마트보유한요소와 Constant-gain feed back control 기법을 이용하여 압전감지기와 압전작동기를 이용한 보구조물의 자유진동제어에 대한 유한요소 모델을 제안한다

• 한국세라믹학회지
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• 제53권2호
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• pp.171-177
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• 2016

Rhombohedral $Ba(Ti_{0.92}Zr_{0.08})O_3$ single crystals are fabricated using the cost-effective solid-state single crystal growth (SSCG) method; their dielectric and piezoelectric properties are also characterized. Measurements show that (001) $Ba(Ti_{0.92}Zr_{0.08})O_3$ single crystals have an electromechanical coupling factor ($k_{33}$) higher than 0.85, piezoelectric charge constant ($d_{33}$) of about 950 [pC/N], and piezoelectric voltage constant ($g_{33}$) higher than 40 [${\times}10^{-3}Vm/N$]. Especially the $d_{33}$ of (001) $Ba(Ti_{0.92}Zr_{0.08})O_3$ single crystals was by about six times higher than that of their ceramics. Because their electromechanical coupling factor ($k_{33}$) and piezoelectric voltage constant ($d_{33}$, $g_{33}$) are higher than those of soft PZT ceramics, it is expected that rhombohedral (001) $Ba(Ti_{0.92}Zr_{0.08})O_3$ single crystals can be used as "lead-free" piezoelectric materials in many piezoelectric applications such as actuator, sensor, and transducer.

• 한국전기전자재료학회논문지
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• 제30권10호
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• pp.637-640
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• 2017

In this study, $(1-x)(Na_{0.52}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3-x(Bi_{0.5}(Na_{0.7}K_{0.3})_{0.5}ZrO_3$ ceramics were fabricated by BNKZ substitution using a conventional solid-state method to develop excellent lead-free piezoelectric ceramics for piezoelectric actuators; their dielectric and piezoelectric properties were then investigated. All specimens were in the orthorhombic phase. $NKL-NSTO_3$ ceramics with x=0.01 showed excellent piezoelectric properties. The density (${\rho}$), piezoelectric charge constant ($d_{33}$), planar piezoelectric coupling coefficient ($k_p$), mechanical quality factor ($Q_m$), and dielectric constant (${\varepsilon}_r$) had optimized values of $4.56g/cm^3$, 208 pC/N, 0.43, 96, and 975, respectively.

• 대한전기학회논문지
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• 제44권4호
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• pp.479-482
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• 1995

In this study, to improve sintering condition, anisotropic properties ( $k_{t}$/ $k_{p}$) of electromechanical coupling coefficient and piezoelectric constant $d_{h}$ and $g_{h}$, Mn $O_{2}$ impurity was added to the (P $b_{0.76}$C $a_{0.24}$)[( $Co_{1}$2/ $W_{1}$2/)$_{0.04}$ $Ti_{0.96}$] $O_{3}$ ceramics for application to hydrophone devices. Electromechanical coupling coefficients of the specimen with 1.5 [mol%] Mn $O_{2}$ sintered at 1150.deg. C were $k_{t}$=49% and $k_{p}$ = O, which exibited the highest value in piezoelectric anisotropic properties (kt/kp). Without relations with sintering temperature, the highest value of hydrostatic piezoelectric constant $d_{h}$ & $g_{h}$ were shown at the specimen with 1.5 [mol%] Mn $O_{2}$. Accordingly, the best addition amount of Mn $O_{2}$ was 1.5 [mol%] and proper sintering temperature was 1150.deg. C. Hydrostatic piezoelectric constant values of $d_{h}$=64.52[10$^{-12}$ C/N], $g_{h}$=35.92[10$^{-3}$ Vm/N] in the above condition were effectiely extended for hydrophone applications.pplications.ons.

• 한국전기전자재료학회논문지
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• 제22권6호
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• pp.484-488
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• 2009

In this study, in order to develop the lead-free piezoelectric ceramics with high piezoelectric and dielectric properties, $[(K_{0.5}Na_{0.5})_{0.95}Li_{0.05}(Nb_{0.96}Sb_{0.04})]O_3$ ceramics were fabricated using $Ag_2O$ as sintering aid and a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $SrTiO_3$ substitution. $SrTiO_3$ substitution enhanced density, dielectric constant(${\varepsilon}_r$) and electromechanical coupling factor($k_p$). However, mechanical quality factor was deteriorated. And also, Curie temperature ($T_c$), and phase transition temperature($T_p$) were rapidly decreased. At the 0.5 mol% $SrTiO_3$ substitution, density, electromechanical coupling factor($k_p$), dielectric constant(${\varepsilon}_r$) and piezoelectric constant($d_{33}$) of specimen showed the optimum value of $4.437\;g/cm^3$, 0.457, 1294, 265 pC/N, respectively.

• 한국전기전자재료학회논문지
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• 제30권4호
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• pp.218-222
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• 2017

In this paper, in order to develop excellent composition ceramics for a piezoelectric energy- harvesting device, we synthesized $0.99(Na_{0.52}\;K_{0.443}\;Li_{0.037})(Nb_{0.883}\;Sb_{0.08}\;Ta_{0.037})O_3$ + $0.01(Sr_{0.95}Ca_{0.05})TiO_3$ + $0.3\;wt%\;Bi_2O_3\;+\;0.3\;wt%\;Fe_2O_3\;+\;0.3\;wt%\;CuO$ (abbreviated as NKN-SCT) ceramics with different sintering times, using the ordinary solid-state reaction method. The effect of sintering time on the microstructure and piezoelectric properties was investigated. The ceramics with the sintering time of 7 h have the optimum values of the piezoelectric constant ($d_{33}$), piezoelectric voltage constant ($g_{33}$), planar piezoelectric coupling coefficient (kp), mechanical quality factor (Qm), and dielectric constant (${\varepsilon}r$): $d_{33}=314[pC/N]$, $g_{33}=20.07[10^{-3}mV/N]$, kp = 0.442, Qm = 93, ${\varepsilon}r=1,768$, all being suitable for a piezoelectric energy-harvesting device.

• 대한전기학회논문지
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• 제36권7호
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• pp.447-452
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• 1987

In this paper, the dependence of piezoelectric properties in the 0-3 composite system of piezoelectric-ceramics polymer materials on particle size of ceramics were investigated. Radial mode and thickness mode of composite were observed similar to single phase of piezoelectric ceramics. The measured values of dielectric constant and dissipation factor were dependent on particle size, which increased with the increasing particle size. the planar coupling factor, thickness coupling factor and thickness frequency constant with the particle size were almost constant, while planar frequency constant increased. The thickness coupling factor decreased with the increasing thickness of specimen. It is found that maximum voltage coeffidient was calculated on the specimen with particle size smallar than 46 ${\mu}m$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.66-67
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• 2005

In this study, in order to develop multilayer piezoelectric actuator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3-Na_2CO_3$ as sintering aids and their piezoelectric and dielectric characteristics were investigated with the function of PNN substitution. With increasing PNN substitution, dielectric constant(${\varepsilon}r$), electromechanical coupling factor(kp), and piezoelectric d constant($d_{33}$) were increased at 10~12[mol%] PNN substitution and then decreased at all sintering temperature. With increasing PNN substitution, phase changed from tetragonal to rhombohedral at [10~12mol%] PNN substitution. At the 12[mol%] PNN substituted PMN-PZT composition ceramic sintered at 950[$^{\circ}C$], density, ${\varepsilon}r$, kp, $d_{33}$ and Qm showed the optimum value of 7.79[$g/cm^3$], 1160, 0.599, 419[pC/N) and 894, respectively for multilayer piezoelectric actuator application.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.795-800
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• 2003

The dielectric and piezoelectric properties of the xPb(A $l_{0.5}$N $b_{0.5}$) $O_3$-(1-x)Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_3$ [xPAN-(1-x)PZT] thin films by pulsed laser deposition (PLD) were investigated as a function of PAN contents. The effect of texture on dielectric and piezoelectric properties of the 0.05PAN-0.95PZT thin films having the highest piezoelectric constant( $d_{33}$) was studied more precisely. For 0$\leq$x$\leq$0.15 compositions in xPAN-(1-x)PZT thin films, the well-developed perovskite phase with (111) preferred orientation was obtained at the deposition temperature of 50$0^{\circ}C$. With increasing PAN content, remanent polarization and coercive field decreased. The dielectric constant increased with an increase of PAN content until it reached 1450 at $\chi$= 0.05, and then decreased for higher PAN content. The maximum points of dielectric constant coincides with the maximum points of the piezoelectric constant $d_{33}$.33/.33/././.